The present invention relates to an object reflector detection system for detecting an object reflector in the field of surveying using laser beam, in which polarized irradiation beam is irradiated from a main unit to the object reflector and the polarized reflection beam reflected by the object reflector is detected.
In order to determine reference of height in the field of civil engineering and architectural technique, laser rotary irradiation system for rotary scanning of polarized irradiation beam in a horizontal plane is now used.
In recent years, visible semiconductor laser has been developed for practical application, and a laser rotary irradiation system using the visible semiconductor laser has also appeared, and this has made it possible to perform visual surveying. In such a laser rotary irradiation system, laser output is restricted in order to ensure safety for operators. For this reason, working distance has become relatively short in the surveying and measurement requiring visual confirmation of reflection of the polarized irradiation beam.
In this respect, a laser rotary irradiation system is currently used, in which polarized irradiation beam is reciprocally scanned to increase apparent luminance of the polarized reflection light beam and working distance is elongated. In order to achieve reciprocal scanning within adequate range, it is necessary to identify scanning position. For this purpose, an object reflector detection system is used, in which an object reflector is arranged at a working point and polarized reflection light beam from the object reflector is detected, and the position of the object reflector is identified.
In the object reflector detection system as described above, in order to identify the object reflector, outgoing light is polarized in such manner that a direction of polarized reflection light from the object reflector changes in proportion to polarizing direction of the outgoing light. This is to discriminate from unnecessary reflector such as glass surface, which has a property to reflect light by preserving polarizing direction.
In the laser rotary irradiation system as described above, reflection light is detected by detecting means corresponding to polarized light from the object reflector. There are often many unnecessary reflectors at the working site for civil or architectural engineering, and the modes of reflection are not constant, containing various polarizing components.
For this reason, in case strong reflection light enters detector of main unit, e.g. in case laser beam from the laser rotary irradiation system perpendicularly hits unnecessary reflector having lustrous surface, or in case reflection light reflected from reflecting object optically similar to the object reflector enters detector of main unit, it is often erroneously detected as an object reflector, and reciprocal scanning is often performed at erroneous position.